Analysis of artemisinin in plant extracts of Artemisia annua L. cultivated in Brandenburg

Artemisia annua L. (Asteraceae) has been used by Chinese folk medicine for many centuries in the treatment of illnesses like fever and malaria. In the 1970s artemisinin, the active agent of the plant, was discovered and isolated. Combination therapies that include artemisinin are the preferred treatments for malaria and are both effective and well tolerated in patients. Today the most used method of artemisinin production is the extraction of plant material [1]. The demand of artemisinin for drug production is very high and can only be satisfied by farming of Artemisia annua at big areas. For a study of optimal farming the cultivation of A. annua was carried out in different variants like open ground and greenhouse in Brandenburg. For the selective determination of the content of artemisinin in raw impure extracts a lot of chromatographic and spectroscopic methods are described [2, 3]. A recent method for the characterization of plant material is metabolic profiling of extracts. By usage of spectroscopic methods like NMR a comprehensive classification of plant material is possible and provides valuable information about secondary metabolite constitutions at selected harvesting time points or planting regions. We used the direct determination of artemisinin by 1H-NMR spectroscopy without purification of the raw extracts. Quantification was carried out analyzing the NMR chemical shifts of artemisinin. Using a reference standard of pure artemisinin we determined artemisinin contents between 0.02 and 0.5%.

Acknowledgements: The authors like to thank the Ministerium für Wirtschaft of Brandenburg and the EU for their support.

References: 1. Lapkin, A. A. et al. (2006)J. Nat. Prod. 69: 653–1664.

2. Castilho, P. C. et al., (2008) Phytochem. Anal. 19: 329–334.

3. Marchand, E. et al. (2008) Biomed. Chromatogr. 22: 454–459.